Sexual transmission of equine herpesvirus-1 (EHV-1) in horses has been proposed by researchers in a Belgian study, with a strain known to cause abortions found to have a liking for the vaginal lining.
The study team set out to learn about the replication and invasion characteristics of EHV-1 and EHV-3 in the mucus membranes of the nasal passage and vagina of horses.
The researchers used tissue samples taken from healthy horses aged 5-10. They were maintained in a laboratory setting and inoculated with a strain of EHV-1 known to cause neurological disease, an EHV-1 strain known to cause abortions, and a strain of EHV-3.
EHV-3 has been associated with both genital and respiratory diseases.
The samples were monitored for 72 hours, during which the three virus strains successfully replicated.
EHV-3 was restricted to replicating in epithelial cells, the study team reported.
EHV-1 was found to replicate far better in the nasal mucosa than the vaginal mucosa, whereas the opposite was found for EHV-3.
Haileleul Negussie and his colleagues reported that the extent of replication of the EHV-1 strain known to cause abortions was significantly higher in the vaginal mucosa than the strain that causes neurological disease.
“Our study has shown that EHV-1 has developed in evolution a predisposition for respiratory mucosa and EHV-3 for vaginal mucosa,” the researchers reported in the journal, Veterinary Research.
Discussing their findings, the researchers said that although they clearly demonstrated that both EHV-1 types were capable of replicating in the vaginal lining, it was much higher with the abortion-causing strain.
“Previous reports indicated that EHV-1 has been isolated from male genital organs and is shed with the semen and the sperm cells.
“When we combine the latter reports with our findings, we could propose a possible venereal transmission of EHV-1 via the semen, which was largely ignored before.”
They noted that venereal transmission had been well documented for other alphaherpesviruses, including EHV-3.
“Therefore, our study highlights an important insight that should be further investigated in the field.”
Negussie was joined in the study by Yewei Li and Hans Nauwynck, all from Ghent University; and Tesfaye Sisay Tessema from Ethiopia’s Addis Ababa University.
Replication characteristics of equine herpesvirus 1 and equine herpesvirus 3: comparative analysis using ex vivo tissue cultures.
Haileleul Negussie, Yewei Li, Tesfaye Sisay Tessema and Hans J. Nauwynck.
Veterinary Research 2016 47:19 DOI: 10.1186/s13567-016-0305-5